Same Side Interior Angles

Same Side Interior Angles

Same side interior angles are two angles that are on the same side of the transversal and on the interior of (between) the two lines.

 $If\ l\parallel m,\ then\ m\angle1+m\angle2\ =\ 180\degree$  

Same Side Interior Angles Theorem: If two parallel lines are cut by a transversal, then the same side interior angles are supplementary.

Converse of the Same Side Interior Angles Theorem: If two lines are cut by a transversal and the same side interior angles are supplementary, then the lines are parallel.

Fill in the Blanks

Multiple Choice

Which choices are two examples of same side interior angles in the diagram:

• $\angle6\ and\ \angle10\ and\ \angle8\ and\ \angle12$

• $\angle1\ and\ \angle9\ and\ \angle3\ and\ \angle11$

Multiple Choice

What is the value of x?

• $30\degree$

• $35\degree$

Multiple Choice

Find the value of y.

y is a same side interior angle with the marked right angle. This means that 90 + y = 180

• 90

• 30

Multiple Choice

Find the value of x

if m∠3 = ( 3x+12) and m∠5 = (5x+8)

• 25

• 20